Connecting a PV panel to a Portable Power Station

[WorldwideDave]

Hello and thanks for reading!
My goal: charge a portable power station/generator via the sun only.

I have a Grecell Portable Power Station HW01.
It uses a LiFePO4 battery.
It has a built-in BMS.
It is also cloudy and shady where I am putting the panel.
I simply want to charge the power station using this panel.
The power station has a built in MPPT it says. 12V-24V, 2.5A seems to be supported.

I also have a 200 Watt Foldable Monocrystalline Solar Panel with Anderson connectors with an open circuit voltage of 23.7. Max power current is 10.1 A and max power voltage is 19.8V. What I don't know is whether or not charging will work. I somehow doubt I'll be getting a full 200 watts, but maybe. I think i read that the HW01 power station can handle up to 120 Watts, but not 200. Given the specs of this panel, will I fry my power station?

I have extension wires from the anderson connector on the panels to an adapter that is likely a 5 MM or so. I believe this will work into this power station as far as plugging in goes.

If I cannot use this panel, what could I use to limit the watts coming out of the panel, if possible? Thank you so much!

 

[wpns]

It feels like the MPPT input will only draw 2.5 amps max from your panel (this is apparently how other MPPT devices work) but maybe the vendor’s tech support could confirm that?

 

[WorldwideDave]

Was hoping other owners of this or other power stations may know.

I do have another MPPT that is not great that I could plug in before going into this device's DC IN port, but that seems hacky.

 

[wpns]

Was hoping other owners of this or other power stations may know.

I do have another MPPT that is not great that I could plug in before going into this device's DC IN port, but that seems hacky.

That does seem like a hack. Given that it's a 'gasoline' generator with a color of '300W', even the vendor may not know.

Is it https://www.amazon.com/GRECELL-Portable-Station-Charging-Generator/dp/B0CQNNCVCX ?
The single 3-star review complains that it has non-standard solar panel connectors and shows a picture of an MC-4 to barrel adapter.

So logically, power supplies are rated in volts (it will put out this much) and amps (do not exceed this, but feel free to draw any amount less than this). And solar panels are rated in Isc (you can't get any more than this, but you can certainly draw less, though the voltage will rise to as much as Voc) and charge controllers are rated in volts (must be in this range) and amps (*), I'd say give it a try. Maybe with a 2.5A fuse inline and a DVM as an ammeter?

(*) While there's some potential ambiguity around amps (is it "I will draw as much as 2.5A", or "I will maximize power even at the expense of drawing so much current that I blow up"?), every other MPPT on the planet seems to mean "I can't draw more than <Amps>, so adding more panels and increasing Isc doesn't do anything bad, it just under-utilizes your panels".

There's a secondary concern around running the MPPT at maximum (amps) for long periods of time, if it'll stress the circuitry and reduce it's lifespan, but that's anyone's guess.

Yes, I'm rambling, or brainstorming, or something. 8*)

 

[AmpD]

65w-100w max charge rate. Anything more would be a risk imo

You might be able to hack a buck/boost type module to the dc jacks.. run the solar to a terminal bar and then charge thru all 3 but then again the batteries or bms might decide they don’t like that.

If it were me i would find something to regulate the amps from the panel to the station. Maybe find something to use the excess juice from the panel elsewhere.

You know like a minature low budget 200w capable solar power setup.

 

[KnobCountry]

AmpD that's not how panels work.

The generator will draw power not be forced to consume it.

It will be limited (regulated) to drawing 2.5amps only. The extra goes unused.

This is not a drinking from a firehose situation.

The max voc of the generator is the primary concern.

Don't exceed the max voltage specs and give it some breathing room.

 

[WorldwideDave]

Thank you all for your replies.
I have a 12v LiFePO4 200Ah battery connected to a shunt on the negative side and 2 meters - one for discharge, and one for charging - on both sides of the shunt.

I have a new solar charge controller connected to a fuse. The fuse is connected to the battery positive & shunt on the negative side.

I have the setup indoors today. I currently have no panels connected to it charging - awaiting an inline fuse, and painting my deck bright white because why not.

I also have a new blue sky fuse panel connected to the battery positive and the shunt negative.

I have a conductor going to a barrel-type connecter listed above that this Grecell portable generator requires for DC input.

It is connected and charging from the battery.

The discharge meter on my shunt shows that at 13.25 volts DC I have 67.5 watts and 5.1 amps leaving my battery.

The charge meter on my Grecell portable generator reads 64 watts is coming in to charge it.

I am using 10 gauge wires between everything. Nothing is hot.

I think that what you are saying above is that because the recharging input voltage is currently at 13.25 volts and listed at 5.1 amps that the charge controller *within the Grecell portable generator* is preventing more amps from flowing into it from the fuse panel. The math checks out - 67.575 watts.

Voc is 22 on my 200 watt panel. Yesterday I was able to charge the LiFePO4 battery at 133 watts for several hours. Happy about that - first test with the setup went great.

I think I've just figured something out - correct me if I'm wrong...the reason that the solar panels charge this GRECELL faster is because at 23.7 Volts multiplied by 5.1 amps I get 121 watts max input through the same DC charge port on my Grecell portable generator. Its all about the amps. And this is why the Grecell charges faster from the sun than from the DC battery. Am I figuring this out right?

If I am, what we are saying is that recharging the solar generator I have from the panels will always be a faster process as the 12V battery I have (vs a 24v) and the max of 5 amps of the Grecell solar generator will always restrict the charge time. Did I learn something new today? I feel like I just had an aha moment.

I guess with this new solar charge controller, I can figure out the same max charging rate for my batteries. With a 20 amp controller, and 23.7 volts, I can support a max of 474 watts. I have 300 watts of panels today, but I was going to replace them both (in parallel now - 100+200).

Someone please tell me if I'm doing this right

 

[WorldwideDave]

I want to highlight a benefit to the Grecell I was not expecting. You can run the built in ac inverter to run loads at the same time as a dc input to charge the battery. So as you are draining it you can charge it.

I have another smaller 150Wh generator that when it charges it will stop the a/c inverter. That sucks.

 

[robbob2112]

I want to highlight a benefit to the Grecell I was not expecting. You can run the built in ac inverter to run loads at the same time as a dc input to charge the battery. So as you are draining it you can charge it.

I have another smaller 150Wh generator that when it charges it will stop the a/c inverter. That sucks.

Be careful not to overheat things. In the compact form factor running everything at once at even half power can damage things inside. The small ones like this are generally not good at coolng. This has fans, so long as they keep up you should be good

For charging, watts are watts. Voltage times current equals power (watts). It draws what it can to charge whatever the source is.

Using solar panels is like tapping a water barrel. The tap is a certain size at the barrel and your spigot at the generator is a certain size. Water will never pass though faster than either end allows as they are sitting at the same level and the is no pressure at the barrel.

You do seem to have a bigger spigot at the solar input than the dc input.

And if a cloud passes over your barrel is empty.